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EJC
2016
3 years 1 months ago
Maximum density of induced 5-cycle is achieved by an iterated blow-up of 5-cycle
Let C(n) denote the maximum number of induced copies of C5 in graphs on n vertices. For n large enough, we show that C(n) = a · b · c · d · e + C(a) + C(b) + C(c) + C(d) + C(e...
József Balogh, Ping Hu, Bernard Lidick&yacu...
EJC
2016
3 years 1 months ago
On permutations with bounded drop size
The maximum drop size of a permutation π of [n] = {1, 2, . . . , n} is defined to be the maximum value of i − π(i). Chung, Claesson, Dukes and Graham found polynomials Pk(x) ...
Joanna N. Chen, William Y. C. Chen
EJC
2016
3 years 1 months ago
Abelian bordered factors and periodicity
A finite word is u is said to be bordered if u has a proper prefix which is also a suffix of u, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word...
Émilie Charlier, Tero Harju, Svetlana Puzyn...
EJC
2016
3 years 1 months ago
The descent set polynomial revisited
We continue to explore cyclotomic factors in the descent set polynomial Qn(t), which was introduced by Chebikin, Ehrenborg, Pylyavskyy and Readdy. We obtain large classes of facto...
Richard Ehrenborg, N. Bradley Fox
EJC
2016
3 years 1 months ago
Positive graphs
We study “positive” graphs that have a nonnegative homomorphism number into every edge-weighted graph (where the edgeweights may be negative). We conjecture that all positive ...
Omar Antolín Camarena, Endre Csóka, ...
EJC
2016
3 years 1 months ago
A new line of attack on the dichotomy conjecture
The well known dichotomy conjecture of Feder and Vardi states that for every family Γ of constraints CSP(Γ) is either polynomially solvable or NP-hard. Bulatov and Jeavons reform...
Gábor Kun, Mario Szegedy
EJC
2016
3 years 1 months ago
Invariant measures via inverse limits of finite structures
Abstract. Building on recent results regarding symmetric probabilistic constructions of countable structures, we provide a method for constructing probability measures, concentrate...
Nathanael Leedom Ackerman, Cameron E. Freer, Jaros...
EJC
2016
3 years 1 months ago
Graph limits and hereditary properties
We give a survey of some general results on graph limits associated to hereditary classes of graphs. As examples, we consider some classes defined by forbidden subgraphs and some ...
Svante Janson
EJC
2016
3 years 1 months ago
Bounding the number of hyperedges in friendship r-hypergraphs
For r ≥ 2, an r-uniform hypergraph is called a friendship r-hypergraph if every set R of r vertices has a unique ‘friend’ – that is, there exists a unique vertex x /∈ R ...
Karen Gunderson, Natasha Morrison, Jason Semeraro
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